1. Field of the Invention
The present invention relates to an effective technique to be applied to management for transmission-reception of electronic mail (E-mail) in Internet or in a personal computer communication.
2. Background of the Related Art
E-mail is generally used as a communication tool for business or private use. It is general that such a E-mail is transmitted-received by using each computer connected to LAN in a company or by connecting a personal computer with a telephone line for dial-up connection to a provider for private use.
A business person, who goes out many times, uses often plural kinds of electronic information devices in order to transmit-receive E-mails in any environment for transmitting-receiving E-mail, for example, a desk-top personal computer in an office, a personal digital assistants when going out and a notebook personal computer at a home.
However, when one person uses plural electronic information devices in order to transmit-receive E-mails in this way, it is difficult to manage E-mails integratedly. Therefore, for example, there are cases in that an E-mail is down-loaded twice or more and a needed E-mail is down-loaded by another electronic information device, hereby incapable of being used.
To give further concrete explanations of this problem, a prior art is explained with reference to FIG. 1.
FIG. 1 is an explanatory view showing conventional E-mail management.
In this explanation, an user uses three terminal devices. Explanations are given of a case in that the user uses three terminal devices 101, 102, 103 and E-mails are transmitted-received via a provider server 104 and a telephone line 106.
It is assumed that the user chooses the device 101 such as a portable digital assistant carried when going out, the device 102 such as a notebook personal computer used when moving through rooms, and the device 103 such as desk-top personal computer used by fixing at a location. All of the devices are respectively provided with memories, and it is possible to store down-loaded E-mails in each of memories.
The user, when down-loading an E-mail arriving at the provider server 104, calls the provider server 104 via the telephone line 106 from one of the devices 101, 102 or 103 held at that time, and receives the E-mail by the device 101, 102 or 103 of which an address is given as a dial-up IP in the E-mail. Further, the E-mail in the provider server 104 after receiving may be deleted or stored.
It is assumed that the user, when accessing the provider server 104, down-loads an E-mail 104 in the provider server 104 with the device 101, and then deletes the E-mail 104a from the provider server 104. After this, through the user is necessary to refer or use the E-mail 104a while using the device 202, there is no information of the E-mail 104a in the memory of the device 202. In other words, the E-mail 104a exists only in the memory of the device 101, therefore, the user can not refer the E-mail 104a when not keeping the device 101 at hand.
To prevent such a case, it is necessary to remain the E-mail 104a without deleting the E-mail 104a from the provider server 104 after down-loading the E-mail 104a with one of the devices (101, 102 or 103) in order to keep a situation in that the E-mail 104a can be used again.
However, in this use style, enormous E-mail information will remain in the memory of the provider server 104, and a large quantity of already-read E-mails obstructs to receive a new E-mail. As a result, there is a possibility in that E-mail management is directly obstructed in the provider server 104.